I didn't always understand that. My Princeton professors taught me that differences are caused by sexism. Boys are encouraged to achieve, girls to nurture. If we socialize equally, they said, just as many girls will want to go to monster truck rallies and become CEOs. Boys will nurture and more will take up ballet.

Some of it happened. Men did become more nurturing. More women became CEOs.

But no amount of government force and corporate "diversity, integrity, governance" programs will equalize the numbers.

Plenty of science shows that men and women are just programmed differently. Google banning talk about that is appalling. (Though owners can do as they like with their companies.)

When I was at ABC News, I did a TV special titled "Boys and Girls Are Different."

On the show, the Kinsey Institute's former director explained that right after birth, males and females behave differently: "Males startle more ... (G)ive a little puff of air on their abdomen, they (are) much more likely to startle." And females move their lips more than males.

Infant girls usually sit up without support before boys; boys crawl away from their caretakers sooner. This happens before parents, or society, have much influence.

Even male baby monkeys like playing with trucks more than female monkeys do.

When I reported that, I got a taste of the Damore treatment.

A "20/20" correspondent confronted my TV producer in the ladies room, asking, "How could you have worked on that disgusting show?"

At the time, fire departments had just dropped strength tests to help female applicants. One critic of the change complained that instead of being carried out during a fire, now she would be dragged downstairs, her head hitting each stair. Steinem responded, "It's better to drag them out ... (L)ess smoke down there."

This is nuts.

It was also nuts more recently when tennis commentator John McEnroe was attacked for saying that if Serena Williams played with men she'd be ranked "like 700."

Why is this even controversial?

Men and women are simply different, and we should acknowledge that difference.

Yes, America was extremely sexist just 50 years ago. It was taboo for women to smoke, wear pants in public or to go a bar alone. A woman couldn't get a credit card without a husband's or father's signature. Really.

Today, though, company heads are less likely to be female not simply because of sexism but because women are less crazy than men -- less likely to be career-obsessed or to take stupid risks for money. That's also a reason there are fewer women in jail. Is that a bad thing?

Women live longer, have more friends, create better work-life balances.

Social engineers may dream of a society where genders are exactly equal. But it's not going to happen. Companies and governments trying to force it will just make life worse.